Anything's possible. But statistically speaking, we're looking at a loss less total environmental damage from the few nuclear incidents that have happened vs. the damage caused by tons and tons of carbon and toxins being spewed by coal plants.

I like to think of it like car crashes vs. plane crashes. Plane crashes are much more publicized, and definitely cause more death/damage per occurrence than a car crash. But because there's so few of them, planes are still much safer overall than cars.